Newsletter Articles : Cryogenic Safety Continues

There are some essential, primary safety items that are required for handling Cryogenic Liquids. Let's use Liquid Nitrogen as an example. It is cold, very cold; it is a bone chilling, skin freezing 321 degrees below zero F.

One drop in your eye would freeze the lens of your eye and shatter it like fine crystal. This would obviously be an extremely painful event and would surely result in the loss of the eye. So, let's cover some basic safety equipment that should be utilized whenever handling liquid nitrogen.

Safety Glasses

A polycarbonate face shield over the safety glasses

A head gear with a ratchet back that can be adjusted to fit any user, to hold the above face shield

This equipment should be stored in close proximity to where the Liquid Nitrogen will be handled so it is readily available to the user

Now let's protect the skin. Liquid Nitrogen droplets on exposed skin can cause painful frostbite burns so a waterproof cryogenic safety glove is recommended. This material is also available in aprons and additional items for more protection.

When transferring Liquid Nitrogen from a Liquid Nitrogen dewar to another vessel it is strongly recommended that an armor cased stainless steel transfer hose is used. Be sure not to close the system and trap Liquid Nitrogen in a hose without a safety relief valve in place. Liquid Nitrogen will expand at 700 times its own volume and it does so very quickly.

Never use a rubber hose to transfer Liquid Nitrogen. The extreme cold and thaw will make tiny cracks in the rubber and flake the rubber particles into the application where it does not belong. The continued freeze / thaw cycle will eventually crack the rubber hose and a failure and spill will occur.

If you are transferring the Liquid Nitrogen into an open container utilize a Phase Separator on the end of the hose to smooth out the flow of the fluid. If you took the filter screen off of the end of the faucet in your kitchen, the water would splash everywhere.

A Phase Separator serves the same purpose. It helps the Liquid Nitrogen to flow evenly and smoothly into the secondary container without excess splashing.

All of the equipment mentioned above is available at Middlesex Gases & Technologies along with many more safety tips. Call me any time to discuss your applications.